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New
microscopy advances biological imaging to nanoscale
28 March 2005
Scanning probe microscopes, usually applied to imaging inorganic
materials at nano- to microscopic scales, may soon be giving
researchers new insights into the biomechanical structures and
functions of living organisms—for example, nature's engineering of a
butterfly's wing.
Sergei Kalinin, a Eugene P.
Wigner Fellow at DOE's Oak Ridge National Laboratory, and Alexei
Gruverman, a research professor at North Carolina State University,
have obtained images of the structure of a Vanessa virginiensis
(American Lady) butterfly's wing at approximately 10 nanometer
resolution.
Their experiment demonstrates that emerging advances in scanning probe
microscopy can be applied to more than hard inorganic materials such
as superconductors and semiconductors. Although the images are “a
proof of concept” it is a concept that could eventually provide clues
to the functionality of complex hierarchical biological systems such
as bones, teeth and other biological tissues.
Nevertheless, even the early results provide clues to the complex
structure behind the elasticity and relative durability of the
splendidly functional butterfly wing.
“Scanning probe microscopy provides unlimited opportunities for
understanding material structure, properties, and functionality at all
length scales,” says Kalinin . “This will pave the way to better and
cheaper materials for biological and medical applications.”
Kalinin's and Gruverman's work with imaging biological systems has its
roots in the development of
atomic force microscopy in the 1980s. Now they are using a
technique called Atomic Force Acoustic microscopy, AFAM, which uses
tiny blasts of sound to probe not only the surface but also the
subsurface structures of delicate biological materials, with
approximately five nanometer resolution.
“This improved imaging sheds lights on how biological systems work,
down to the five-nanometer resolutions, which is comparable to the
size of a DNA molecule-about as small as you need for biological
materials,” says Kalinin. “Biosystems, because they are not ordered
like, for instance, crystalline materials, require real-space imaging
of local elastic properties and structure. Scanning probe microscopes
are a wonderful tool that is suited for exactly this purpose.”
“Scanning probe microscopy is a key to the advancement of nanoscience,”
says Kalinin . “It is a new field and it develops rapidly, so novel
methods appear virtually overnight. However, it takes a sustained
interdisciplinary effort before true potential of SPM is realized.”
Source: Oak Ridge National Laboratory |
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